Question

A family uses 8 kW of power. (a) Direct solar energy is incident on the horizontal surface at an average rate of 200 W per square meter. If 20% of this energy can be converted to useful electrical energy, how large an area is needed to supply 8 kW? (b) Compare this area to that of the roof of a typical house.

Answer 1

(a) 200 m²

Power used by the family, P = 8 kW = 8 x 10³ W 

Solar energy received per square metre = 200 W
Efficiency of conversion from solar to electricity energy = 20%
Area required to generate the desired electricity = A
As per the informationgiven in the question, we have:

The area of a solar plate required to generate 8 kW of electricity is almost equivalent to the area of the roof of a building having dimensions 14 m x14 m.